CN116525268A

CN116525268A - Magnetic element, power module and preparation method of magnetic element

Info

Publication number: CN116525268A
Application number: CN202210068306.5A
Authority: CN
Inventors: 洪守玉; 陈庆东; 毕帅然; 万千; 王增胜; 周甘宇; 付志恒; 周锦平; 叶益青
Original assignee: Delta Electronics Shanghai Co Ltd
Current assignee: Delta Electronics Shanghai Co Ltd
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2023-08-01
Also published as: EP4216243A1; US20230230761A1

Abstract

The invention provides a magnetic element, which comprises a magnetic core and a magnetic core, wherein the magnetic core comprises at least one magnetic column, and the magnetic column extends along a first direction; a first winding surrounding the outside of the magnetic pole; a second winding at least partially surrounding the outside of the first winding, the number of turns of the second winding being less than or equal to the number of turns of the first winding; and a third winding at least partially surrounding the second winding, the number of turns of the third winding being less than or equal to the number of turns of the first winding. The invention improves the reliability of the magnetic element and better balances the pin loss and the conduction loss of the multilayer winding.

Description

Magnetic element, power module and preparation method of magnetic element

Technical Field

The invention relates to the technical field of power supplies, in particular to a magnetic element, a power module and a preparation method of the magnetic element.

Background

With the rise of human demands for intelligent life, society demands for data processing increasingly. Global energy consumption in data processing, on average, reaches billions or even trillions per year; while the footprint of a large data center can reach tens of thousands of square meters. Therefore, high efficiency and high power density are key indicators for the healthy development of the industry.

The key unit of the data center is a server, and the main board of the data center is usually composed of a central processing unit (Central Processing Unit, CPU), a chipset (Chipsets), a memory and other data processing chips, and a power supply and necessary peripheral components thereof. With the increase of the processing capacity of the server per unit volume, the number and integration level of the processing chips are increased, which results in the increase of space occupation and power consumption. Therefore, power supplies (also called motherboard power supplies, because they are on the same motherboard as the data processing chips) that are powered by these chips are expected to be more efficient, more power-dense and less bulky to support the energy savings and reduced footprint requirements of the entire server and thus the entire data center. In order to meet the requirement of high power density, the switching frequency of the power supply is also higher and higher, and the switching frequency of the low-voltage high-current power supply in the industry is basically 1 Megahertz (MHz).

For transformers used for low-voltage and high-current applications, higher power density and higher conversion efficiency are still problems to be solved.

Fig. 1 is a schematic structural diagram of a transformer module according to the prior art. As shown in fig. 1, winding R _01B And R is _02B Wound on two magnetic columns of the magnetic core. The structure comprises at least two directions: the winding direction 1015 of the winding and the winding extension 1016 parallel to the magnetic pillar. The dimension of the winding parallel to the length direction of the magnetic pole, namely the dimension of the winding in the extending direction is W, the dimension of the winding perpendicular to the direction of the magnetic pole of the magnetic core is H, namely the thickness of the single-layer winding is H. When H and W satisfy the relationship: when W > 10H, we define this winding mode as foil winding structure winding. In the figure, 1011, 1012 are the legs of the winding, 1013, 1014 are the boundaries of the winding formed in its direction of extension 16. In the transformer of this structure, the pins of each winding connected to the external circuit are usually led out from the side of the winding, i.e. the pins of the inner winding extend beyond the boundary of the outer winding in the extending direction and then are connected to the external circuit, as shown in 1011 and 1012. With this configuration, all the current on the winding flows through the pin, which not only makes the winding current distribution uneven, but also causes a large loss on the pin. In addition, the pins are typically relatively long, which further exacerbates the loss on the pins.

Fig. 2 is a perspective view of another transformer in the prior art. Windings 2021 and 2022 surround the pole 2020, forming the inner and outer windings of the transformer. The outer layer winding 2022 is connected to an external circuit through two output ends 20221 and 20222 thereof; the inner winding 2021 is connected to an external circuit through two output terminals, for example, output terminals 20211 and 20212. 2025 shows the direction in which the inner and outer windings are wound around the magnetic pole, and 2026 shows the direction in which the inner and outer windings extend parallel to the magnetic pole. 2023 2024 is the boundary of the inner or outer winding in its direction of extension. An insulating layer (not shown) is also present between the inner and outer windings, through which insulating layer the inner winding 2021 forms the outlet ends 20211 and 20212 at the transformer surface, and the outlet ends 20211, 20212 are located within the boundaries of the outer winding.

Fig. 3 is a cross-sectional view of the transformer of fig. 2 along a01-a 01'. As shown in fig. 3, the hatched portion 2020 is a cross-sectional view of a magnetic core, wherein the output ends 20211 and 20212 are connected to the two end points 20213 and 20214 of the inner winding 2021 by connection means, such as vias 202111 and 202121, respectively. As can be seen from fig. 3, the connection means of the inner winding 2021 passes through the outer winding 2022 and then is connected to an external circuit. Wherein the projection of the connection means of the inner winding 2021 in the plane of the outer winding 2022 is located within the boundary of the outer winding 2022. This has the advantage that the pin length of the inner winding 2021 is greatly reduced, thereby reducing losses on the pins. In addition, the structure is advantageous to form a distributed output structure, that is, the inner winding 2021 may be connected to an external circuit by a plurality of connection devices, such as vias, metal strips, etc., penetrating the outer winding 2022 to form a plurality of output ends on the surface of the transformer. The distributed output structure effectively reduces the current flowing through each connecting device/pin, and greatly improves the problem of uneven current on each connecting device/pin, thereby further improving the overall efficiency of the transformer.

However, this structure has a problem in that when the inner winding passes through the insulating layer between the inner and outer windings and forms an output end within the boundary of the outer winding, the outer winding is forced to avoid the output end, thereby causing a reduction in the area of the outer winding through which current effectively passes and increasing the loss of the outer winding. In particular, when the inner layer winding passes through the outer layer winding to form a plurality of output ends through a plurality of connecting devices, and projections of the plurality of connecting devices on the surface of the outer layer winding are all located in the boundary of the outer layer winding, a plurality of avoidance areas are formed on the outer layer winding, so that the integrity of the outer layer winding is affected. In the case where the current flowing through the outer layer winding is relatively large, the loss thereof increases significantly. When the outer layer winding is a high-voltage winding, the possibility of insulation failure between the high-voltage winding and the low-voltage winding is greatly increased, so that the reliability of the transformer is affected.

When the number of windings is greater, such as more than three windings, as shown in fig. 4 and 5. The three-layer winding shown in fig. 4 is a winding structure of an SPS, i.e., a primary winding 3023 is disposed between secondary windings 3021, 3022. The secondary winding 3021 is connected to pins 30211 and 30212 formed on the surface of the transformer and connected to an external circuit by connection means. As shown in fig. 4, the formation of the connection device includes two steps. One of the steps is that the winding 3021 passes through the insulation layer between 3021 and 3023 by a part of connection means such as a via hole, and a transfer pin 30213 is formed on the wiring layer where the primary winding 3023 is located; another step is to form pins 30211 and 30212 connected to the external circuit on the wiring layer where 3022 is located by a portion of the connection means such as vias or conductive pillars through the insulating layer between 3022, 3023. Overall, the connection means passes through the insulation between the windings 3021 and 3023, the insulation between the windings 3023, 3023 and 3022, and the pins 30211, 30212 are formed on the wiring layer where the winding 3022 is located. Of course, the connection means may also form pins 30211, 30212 through the winding 3022 on a wiring layer outside the winding 3022. Fig. 4 is a cross-sectional view along the section line B01-B01' based on fig. 5, and it is apparent that since the connection means of the winding 3021 passes through the intermediate layer primary winding 3023, the primary winding 3023 is broken seriously, so that the flow area of the primary winding 3023 is reduced and the impedance is increased.

In addition, in applications where the input is high voltage and the output is low voltage, the primary winding is typically a high voltage winding and has a large number of turns, while the secondary winding is typically a low voltage winding and has a small number of turns. At this time, the connection device of the inner secondary winding 3021 needs to leave a sufficient distance between the two windings to meet the requirement of safety insulation when passing through the primary winding 3023, which particularly shows that the distance between the edge of the transfer pin 30213 and the winding 3023 in fig. 5 needs to meet a certain distance. From the current manufacturing process, when applied at high to low voltages, the inner layer winding is typically a low voltage high current output winding due to the lower voltage of the inner layer winding. In order to reduce losses on the output side, the inner winding is usually connected to an external circuit via a plurality of connections through the outer winding. In the process, an insulating medium layer needs to be paved between the winding 3022 and the winding 3023, and then the insulating medium is pressed into the gap between the adapter pin 30213 and the winding 3023 through a pressing process, and the compactness of the insulating medium between the layers can be well ensured, but the filled gap has the defect of insufficient glue with high probability. In pursuit of higher power densities, the gap between the switch pin 30213 and the winding 3023 will get closer to the process limit when meeting the safety requirements, and thus the problem of underfill will be more likely to occur. This increases the risk of insulation between the high and low voltages of the primary and secondary side, i.e. the reliability of the transformer is reduced.

In order to reduce the insulation risk, to improve the reliability of the transformer, and to better balance the pin losses and the conduction losses of the multilayer winding, the invention provides a new solution.

Disclosure of Invention

The invention aims to provide a magnetic element, a power module and a preparation method of the magnetic element, which are used for improving the reliability of the magnetic element and better balancing the pin loss and the conduction loss of a multilayer winding.

Other features and advantages of the invention will be apparent from the following detailed description, or may be learned by the practice of the invention.

According to a first aspect of the present invention, there is provided a magnetic element comprising:

a magnetic core including at least one magnetic pillar extending in a first direction;

a first winding surrounding the outside of the magnetic pole;

a second winding at least partially surrounding the outside of the first winding, the number of turns of the second winding being less than or equal to the number of turns of the first winding; and

and the third winding at least partially surrounds the outer side of the second winding, and the number of turns of the third winding is smaller than or equal to that of the first winding.

Still another aspect of the present invention provides a power module, including:

A magnetic element as described above;

a first carrier plate at least partially covering a first side surface of the magnetic element;

the first rectification switch tube is positioned on the surface of one side of the first carrier plate, which is away from the magnetic element, and is electrically connected with the second winding through the first carrier plate;

the second rectifying switch tube is positioned on the surface of one side of the first carrier plate, which is away from the magnetic element, and is electrically connected with the third winding through the first carrier plate.

The invention also provides a preparation method of the magnetic element, which comprises the following steps:

providing a magnetic core, wherein the magnetic core comprises at least one magnetic column;

forming a first metal wiring layer on the surface of the magnetic column to obtain a magnetic core assembly, wherein the first metal wiring layer forms a first winding;

providing a bendable substrate, wherein the bendable substrate comprises a second metal wiring layer and a third metal wiring layer, the second metal wiring layer and the third metal wiring layer form a second winding and a third winding, and the number of turns of the second winding and the third winding is smaller than that of the first winding;

combining the bendable substrate with the magnetic core assembly so that the second winding at least partially surrounds the outer side of the first winding and the third winding at least partially surrounds the outer side of the second winding, and obtaining the magnetic element.

Compared with the prior art, the embodiment of the invention has the following technical effects that all or part of the advantages are beneficial:

1. by adopting the magnetic element in the embodiment of the invention, the winding with more turns can be prevented from being penetrated, the loss of the magnetic element is reduced, the reliability of the whole power module is improved, and the possibility of processing safety insulation is provided; 2. the continuous and complete copper sheets are used for replacing the PCB through holes, so that the copper laying efficiency is improved, and the loss is reduced;

3. the bendable substrate is bent around the outer surface of the magnetic core to form a winding, and the medium between the formed side wall windings directly inherits the thickness of the medium before bending, so that the distance between winding layers is reduced, and the volume and the occupied area of the magnetic element are reduced;

4. all the magnetic elements are made of the existing materials, so that the cost is reduced, and the process is simplified.

For a further understanding of the nature and technical aspects of the present invention, reference should be made to the following detailed description of the invention and to the accompanying drawings, which are included to illustrate and not to limit the scope of the invention.

Drawings

The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Fig. 1 is a schematic structural diagram of a transformer module according to the prior art;

FIG. 2 is a perspective view of another transformer according to the prior art;

FIG. 3 is a cross-sectional view taken along the direction A01-A01' in FIG. 2;

FIG. 4 is a cross-sectional view taken along the direction B01-B01' in FIG. 5;

FIG. 5 is a schematic diagram of a transformer according to another prior art;

FIG. 6 is a schematic diagram of a voltage converting circuit according to a first embodiment of the present invention;

FIG. 7 is a schematic structural view of a magnetic element according to a first embodiment of the present invention;

fig. 8 is a plan view of a power module of a first embodiment of the present invention;

FIG. 9 (a) is a cross-sectional view taken along the direction a1-a1' in FIG. 8;

FIG. 9 (b) is a cross-sectional view taken along the direction a2-a2' in FIG. 8;

fig. 10 is a schematic structural view of another power module according to the first embodiment of the present invention;

FIG. 11 is a cross-sectional view taken in the direction b-b' of FIG. 11;

FIG. 12 is a schematic illustration of a magnetic element according to a second embodiment of the present invention;

FIG. 13 is a structure of a magnetic core of a second embodiment of the present invention;

FIGS. 14 (a) to (f) are schematic views showing a process for producing a first metal layer according to a second embodiment of the present invention;

fig. 15 (a) to (c) are schematic views showing a process for manufacturing a bendable substrate according to a second embodiment of the present invention;

FIG. 16 is a schematic view of a magnetic element according to a third embodiment of the present invention;

Fig. 17 (a) - (c) are schematic views of process paths of a bendable substrate according to a third embodiment of the present invention;

fig. 18 is a schematic structural view of a magnetic element with an added stiffening layer according to a third embodiment of the invention;

fig. 19 (a) is a schematic structural view of a power module according to a fourth embodiment of the present invention;

FIG. 19 (b) is a cross-sectional view taken along the direction c-c' in FIG. 19 (a);

fig. 20 is a schematic view of an interposer including an insulating layer according to a fourth embodiment of the present invention;

fig. 21 is a perspective view of a interposer according to a fourth embodiment of the present invention after dielectric insulating layer is peeled off;

FIG. 22 (a) is a schematic diagram of a power module with passive components according to a fourth embodiment of the present invention;

FIG. 22 (b) is a cross-sectional view taken along the direction d-d' in FIG. 22 (a);

fig. 23 (a) is a schematic diagram of a power module employing another interposer according to a fourth embodiment of the present invention;

FIG. 23 (b) is a cross-sectional view taken along the direction e-e' in FIG. 23 (a);

fig. 24 is a schematic view of another interposer including an insulating layer according to a fourth embodiment of the present invention;

fig. 25 is a perspective view of another interposer according to a fourth embodiment of the present invention after dielectric insulation is stripped;

FIG. 26 is a schematic diagram of the structure of a magnetic element according to a fifth embodiment of the present invention;

fig. 27 is a schematic structural view of a magnetic element according to a sixth embodiment of the present invention.

Reference numerals:

etched copper foil with 1-16 pins 59

21-216 power pin 6 adapter plate

41 Boundary 61 first metal wiring layer

43. Second metal wiring layer with parallel extension direction 62 of winding

44. Third metal wiring layer in winding direction 63

45. Fourth metal wiring layer of first winding 64

46. Second winding 65 fifth metal wiring layer

47. Third winding 66 first power pin

48. Fourth winding 67 second power pin

51. Third power pin of first metal layer 68

52. Second metal layer 71 first rectifying switch tube

53. Third metal layer 72 second rectifying switch tube

54. First carrier plate of three-layer insulating medium 81

541. First insulating layer 86 adhesive

542. Second insulating layer 87 conductive sheet

543. Third insulating layers 881-885 bonding layers 1-5

551. First metal protection layer 91 first magnetic pillar

561. First metal wiring layer 911 first magnetic pillar upper surface

562. Second metal wiring layer 92 second magnetic pillar

563. Third metal wiring layer 93 magnetic core

571. Metal plate with bendable base material 95

572. Locally reinforced 951 first end

573. Second end of rigid substrate 952

574. Flexible substrate 96 passive component

575. Reinforcing layer 971 pin

58. Gap 972 connector

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar components, and thus a detailed description thereof will be omitted.

Furthermore, the described features, components, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the inventive aspects may be practiced without one or more of the specific details, or with other components, parts, steps, methods, etc. In other instances, well-known components, parts, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

The structure and fabrication method of the magnetic element and power module of the present invention are described in detail below in conjunction with various embodiments.

Fig. 6 shows a voltage conversion circuit according to a first embodiment of the present invention. As shown in fig. 6, the circuit comprises a first winding formed by a primary winding P, P1 and P2 represent two terminals of the primary winding P, and a second winding and a third winding formed by two secondary windings S1 and S2, which are coupled to each other to form a transformer. Windings S1, S2 are connected in series to node V0; the other node D1 of the winding S1 is connected to one end of the second rectifying switch tube 72, the other node D2 of the winding S2 is connected to one end of the first rectifying switch tube 71, S1 'represents a pin of the first rectifying switch tube 71, and S2' represents a pin of the second rectifying switch tube 72; as shown, windings S1, S2, the first rectifying switch 71, the second rectifying switch 72, and the capacitor are connected to form a full-wave rectifying circuit. The primary and secondary windings can be single-turn or multi-turn.

Fig. 7 is a partial perspective view of a magnetic element of this embodiment. Wherein the magnetic element comprises a magnetic core, a first winding 45, a second winding 46 and a third winding 47. The perspective view shows the first leg 91 of the core and the first winding 45, the second winding 46 and the third winding 47 wound around the leg. The second winding 46 and the third winding 47 may be selected as foil windings. The first magnetic pillar 91 extends along the first direction 43. The first winding 45 surrounds the outside of the first magnetic post 91. The second winding 46 at least partially surrounds the outer side of the first winding 45, and the number of turns of the second winding 46 is less than or equal to the number of turns of the first winding 45. The third winding 47 at least partially surrounds the outer side of the second winding 46, and the number of turns of the third winding 47 is less than or equal to the number of turns of the first winding 46. As shown in fig. 7, a first metal layer 51, a second metal layer 52 and a third metal layer 53 are provided on the surface of the first magnetic pillar 91 from inside to outside, and an insulating layer is provided between the metal layers. The first winding 45 is formed on the first metal layer 51, and the second and third windings 46 and 47 are formed on the second and third metal layers 52 and 53, respectively. The direction 44 shows the direction in which the windings of each layer are wound around the magnetic pillar, and the direction 43 is the direction in which the windings of each layer are parallel to the extension direction of the first magnetic pillar 91, i.e. the first direction. 41 42 is then the boundary of the outermost winding, for example the third winding 47, in its direction of extension. Both ends of the first winding 45 extend along the extension direction 43 beyond the borders 41, 42 of the second winding 46 or the third winding 47 and form the ninth power pin 29 and the twelfth power pin 212 by means of two metal connectors, such as conductive strips 87; the third winding 47 is wound on the first magnetic pillar 91 along the direction 44, and the two ends of the third winding form a first power pin 21 and a fourth power pin 24; the second winding 46 is located inside the third winding 47 and is also wound around the first magnetic pillar 91 in the direction 44, and the two ends of the second winding 46 form the second power pin 22, the third power pin 23 on the surface of the module by means of metal connectors penetrating through the insulation layer between the second winding 46 and the third winding 47. Wherein, the first power pin 21 to the fourth power pin 24 are located between the boundaries 41 and 42. The upper surface of the first magnetic pillar 91 in fig. 7 is defined herein as the first side.

The first projected area of the third winding 47 is set to be an area formed by the vertical projection of the third winding 47 on the plane where the upper surface 911 of the first magnetic pillar 91 is located, and the area includes two boundaries, i.e., boundaries 41, 42 of the third winding 47 in the extending direction thereof; similarly, the area of the first projection of the second winding 46 also includes two boundaries, which may or may not overlap with the two boundaries of the first projection of the third winding. Since the boundaries of the second winding 46 and the third winding 47 overlap in fig. 7, the boundaries of the first projection of the second winding are also 41 and 42. The first pins (e.g., the ninth power pin 29 and the twelfth power pin 212) to which the first winding 45 is connected are formed outside the area of the first projection of the third winding, that is, the first pins of the first winding 45 are located outside the boundaries 41, 42 of the first projection of the third winding. The second leg of the second winding 46 and the third leg of the third winding 47 are located on the first side of the magnetic element (e.g., the upper surface of the magnetic element in fig. 7), and the second leg of the second winding 46 (e.g., the second power leg 22 and the third power leg 23) and the third leg of the third winding 47 (e.g., the first power leg 21 and the fourth power leg 24) are formed in the area of the first projection of the third winding, i.e., the second leg of the second winding 46 and the third leg of the third winding 47 are formed in the boundaries 41, 42 of the first projection of the third winding. Furthermore, the second winding 46 forms a pin on the transformer surface through the insulation between the second winding 46 and the third winding 47. Thus, in this embodiment, the three windings comprise pins that lead from at least two different directions.

The pins of different windings extend out of the boundary from the extending direction and are led out of the boundary, so that the influence of the pins of the inner layer winding on the conductive area of the outer layer winding can be effectively reduced, and the loss of the pins of the outer layer winding can be effectively improved. In particular, one of the first pins (such as the twelfth power pin 212) of the inner layer winding, for example, the first winding 45, extends beyond the boundary of the outer layer winding (such as the second winding 46 or the third winding 47), and the other first pin (such as the ninth power pin) is led out (for example, in a direction perpendicular to the surface of the first magnetic pillar 91, through the metal layer where the second winding 46 is located, and the insulating layers of the second winding 46 and the third winding 47 are led out on the surface of the transformer) within the boundary of the outer layer winding (such as the second winding 46 or the third winding 47), so that the influence on the conductive area of the outer layer winding can be reduced, thereby reducing the loss of the outer layer.

In a typical low voltage high current conversion circuit, the first winding 45 is usually a multi-turn winding, and the second and third windings 46, 47 have fewer turns, usually one turn. And the current flowing through the first winding 45 is relatively small, while the current flowing through the second and third windings 46, 47 is large in order to provide a large current output. Thus, this embodiment provides a magnetic element in which the first winding 45, the second winding 46, and the third winding 47 are provided in this order from the inside to the outside of the surface of the magnetic pillar, the number of turns of the first winding 45 is larger than the number of turns of the second winding 46 and the third winding 47, and the number of turns of the second winding 46 is larger than the number of turns of the third winding 47. Compared with the prior art shown in fig. 2 and 3, the present embodiment adopts a structure in which the winding with more turns is at the innermost layer, and the two windings with fewer turns are at the middle layer and the outer layer. Under this structure, if adopt the mode of pin is drawn forth on the surface after the winding that turns more passes the winding of turns less through connecting device, because the winding of turns less then usually is low-voltage or heavy current winding, its pin quantity is more, and the winding of turns more is usually high-voltage winding, its pin quantity is less, although need dodging the connecting device of turns more winding of turns less then the winding of turns less, dodging the number of times is less, causes the possibility of insulation failure less to the effective conductive area influence of outer winding is also less. In addition, in this embodiment, the innermost winding with more turns is connected to the external circuit after the pins are led out from the connection device outside the projection area, which completely avoids the risk of insulation failure caused by the pins of the first winding in the boundary, and simultaneously avoids the problem of greatly increasing conduction loss on the second winding 46 and the third winding 47 due to the reduction of the effective conduction areas of the second winding 46 and the third winding 47. Compared with the prior art shown in fig. 1, the pin extraction mode in this embodiment effectively reduces the lengths of the large current windings, namely the second winding 46, the second pin of the third winding 47 and the third pin, so as to greatly reduce the losses on the second winding 46, the second pin of the third winding 47 and the third pin.

Fig. 9 (a) and 9 (b) are sectional views of the power module shown in fig. 8 along the first section (a 1-a1 ') and the second section (a 2-a2 '), respectively, and fig. 8 is a top view of the power module along a-a ' corresponding to the voltage conversion circuit shown in fig. 6. As shown in fig. 8 and 9, the power module includes: the magnetic element shown in fig. 7; a first carrier plate 81 at least partially covering a first side surface of the magnetic element; the first rectifying switch tube 71 is located on a surface of the first carrier plate 81, which faces away from the magnetic element, and is electrically connected with the second winding 46 through the first carrier plate 81; the second rectifying switch tube 72 is located on a surface of the first carrier plate 81 facing away from the magnetic element, and is electrically connected to the third winding 47 through the first carrier plate 81. Specifically, the first winding 45, the second winding 46, and the third winding 47 are wound on both legs (the first leg 91 and the second leg 92) of the U-shaped magnetic core. The first rectifying switch tube 71 and the second rectifying switch tube 72 are alternately arranged on the first carrier plate 81, and are electrically connected with the second winding 46 and the third winding 47 through the first carrier plate 81.

Further, with reference to fig. 7, 8, 9 (a) and 9 (b), the first to fourth power pins 21 to 24 extend from the boundary 41 to the boundary 42, and the length of the pins becomes long; accordingly, the area of the pins increases, the number of the switching elements, i.e. the first rectifying switch 71 and the second rectifying switch 72, connected to each pin increases, for example, on one magnetic pillar in fig. 8, and the first to fourth power pins are respectively connected to the two first rectifying switch 71 and the two second rectifying switch 72, which makes the current distribution on each pin more uniform, and effectively reduces the loss on the pins. In addition, the first rectifying switch tube 71 and the second rectifying switch tube 72 are staggered in the extending direction, so that the current is further uniformly distributed, and the pin loss is further reduced.

Alternatively, the first winding 45 may be led out horizontally directly, i.e. without the conductive sheet 87. That is, the first winding 45 is led out of the pin directly in the direction of extension.

Referring to fig. 8 and 9 (a), 9 (b), the magnetic element further includes a second magnetic pillar 92, and the power module includes the magnetic element, the first carrier plate 81, and the device on the first carrier plate described in the foregoing embodiments. The magnetic element, the first carrier 81 plate and the device are stacked in the thickness direction. Further observation shows that the secondary windings of the magnetic element corresponding to the first magnetic pole and the secondary windings of the magnetic element corresponding to the second magnetic pole are connected through adhesive 86, i.e. are not electrically connected with each other. The secondary winding of the magnetic element is electrically connected to the secondary rectifier switching tube via the metal wiring layer of the first carrier plate 81. Therefore, the first magnetic column unit and the bendable substrate can be assembled after being bent, and the second magnetic column unit and the bendable substrate can be assembled after being bent, so that the first magnetic column unit and the bendable substrate can be independently assembled without considering electrical connection, and the manufacturing process is simpler. The first magnetic pillar unit includes a first magnetic pillar 91 and a first metal layer clad therewith, and the second magnetic pillar unit includes a second magnetic pillar 92 and a first metal layer clad therewith.

With reference to fig. 6 and 8, the primary winding P forms a primary pin on the upper surface of the magnetic element: the ninth power pin 29, tenth power pin 210, eleventh power pin 211, and twelfth power pin 212, and the secondary winding S1 forms a secondary pin on the upper surface of the magnetic element: a third power pin 23, a fourth power pin 24, a seventh power pin 27, an eighth power pin 28; the secondary winding S2 has a first power pin 21, a second power pin 22, a fifth power pin 25, and a sixth power pin 26 formed on the upper surface of the magnetic element. The primary winding P corresponds to the first winding 45, the secondary winding S1 corresponds to the second winding 46, and the secondary winding S2 corresponds to the third winding 47. The first side surface of the magnetic element is also provided with a plurality of signal pins, and the projection of the signal pins on the first side surface of the magnetic element is not overlapped with the first projection of the first pins, the first projection of the second winding and the first projection of the third winding. That is, as shown in fig. 8, the upper surface of the magnetic element further includes pins 1-16, which can be used for signal routing, driving, controlling, power, etc.

In another alternative embodiment, the second pin and the third pin are respectively disposed on a second side of the magnetic element. The second side of the magnetic element is herein a different side surface than the first side. For example, in the perspective of fig. 7, a first side of the magnetic element is an upper surface and a second side of the magnetic element is another side than the upper surface, such as a lower surface of the first magnetic pillar. And a second pin second projection and a third pin second projection on a second side of the magnetic element, respectively, the second winding and the third winding having a second winding second projection and a third winding second projection on a second side surface of the magnetic element, respectively. The second pin second projection is located within the second winding second projection, the second winding second projection having two boundaries aligned along the first direction, the second pin second projection extending from one boundary to another boundary of the second winding second projection. The third pin second projection is located within the third winding second projection, the third winding second projection having two boundaries aligned along the first direction, the third pin second projection extending from one boundary to another boundary of the third winding second projection.

The magnetic element may further include a conductive member (such as conductive sheet 87 shown in fig. 7) that is surface-mounted to the first winding 45 such that an upper surface of the conductive member, an upper surface of the second pin, and an upper surface of the third pin are coplanar. Specifically, since the first winding 45 is formed on the first metal layer, the second winding 46 and the third winding 47 are formed on the second and third metal layers and at least partially cover the first metal layer, there is necessarily a height difference between the windings in the thickness cross-section direction. To solve the coplanarity problem of the first pin of the first winding 45, the second pin of the second winding 46 and the third pin of the third winding 47, the first winding pin can be formed by surface-attaching the conductive members 29 and 212 to the first winding 35, so as to compensate the height difference by using the height of the conductive members, and realize coplanarity of all pins on the upper surface of the magnetic element, as shown in fig. 7. The coplanarity of the pins is improved, and the welding yield can be effectively improved.

With continued reference to fig. 8, 9 (a) and 9 (b), it can be seen that the second power pin 22 of the magnetic element is connected to the lower surface of the first carrier plate 81, and is connected to the pin D1 of the first rectifying switch tube 71 through the metal wiring layer of the first carrier plate 81; the fourth power pin 24 is connected with the lower surface of the first carrier plate 81 and is connected with a pin S1' of the first rectifying switch tube 71 through a metal wiring layer of the first carrier plate 81; the third power pin 23 is connected with the lower surface of the first carrier plate 81 and is connected with a pin D2 of the second rectifying switch tube 72 through a metal wiring layer of the first carrier plate 81; the first power pin 21 is connected to the lower surface of the first carrier plate 81, and is connected to the pin S2' of the second rectifying switch tube 72 through the metal wiring layer of the first carrier plate 81. It is also apparent from a comparison of fig. 9 (a) and 9 (b) that the metal wiring layers for connecting D1 and D2 are staggered in the first carrier plate 81. The first carrier board 81 can be implemented by a PCB technology, which is mature and flexible in routing. Similarly, the pins above the second magnetic columns 92 are connected to the first rectifying switch tube 71 and the second rectifying switch tube 72 through the metal wiring layer of the first carrier plate 81, and the specific connection manner can refer to the first magnetic columns 91, which is not described herein. The staggered wires are arranged on the first carrier plate 81, so that the requirement on the magnetic element can be greatly reduced, and the manufacturing difficulty of the magnetic element is further reduced.

With continued reference to fig. 9 (b), since the second windings 46 and the third windings 47 are staggered, a portion of the second windings 46 is outside the third windings 47. With continued reference to fig. 8, the first rectifying switch tube 71 and the second rectifying switch tube 72 on the upper surface of the first carrier 81 are arranged in a linear staggered manner along the long sides of the first magnetic column 91 and the second magnetic column 92, and the staggered arrangement can make the current flowing through the first rectifying switch tube 71 and the second rectifying switch tube 72 uniform, so that no larger current is concentrated, and the loss is smaller.

In order to further achieve a more uniform current distribution, this embodiment also provides a stacked structure of another power module, as shown in fig. 10 and 11. Wherein fig. 10 is a stacked structure of another power module, and fig. 11 is a top view along the b-b' direction in fig. 10. Referring to fig. 10 and 11, unlike fig. 8, 9 (a) and 9 (b), a first rectifying switch tube 71 and a second rectifying switch tube 72 are provided on the upper surface of a first magnetic column 91, and the first rectifying switch tube 71 and the second rectifying switch tube 72 are divided into two columns. Similarly, the first rectifying switch tube 71 and the second rectifying switch tube 72 are disposed above the second magnetic pole 92, and the first rectifying switch tube 71 and the second rectifying switch tube 72 are divided into two rows. In comparison with the distribution characteristics of the first rectifying switch tube 71 and the second rectifying switch tube 72 shown in fig. 8, 9 (a) and 9 (b), the arrangement mode shown in fig. 10 and 11 enables the current to be distributed to the 4 first rectifying switch tubes 71 located in the same column approximately evenly through the metal wiring layer of the first carrier plate 81, and likewise, the current is distributed to the 4 second rectifying switch tubes 72 located in the same column approximately evenly through the metal wiring layer of the first carrier plate 81, so that the arrangement of the first rectifying switch tube 71 and the second rectifying switch tube 72 shown in fig. 10 and 11 can achieve better current sharing effect, and loss can be further reduced.

Corresponds to the structure of the magnetic element of the first embodiment. The first winding, the second winding and the third winding are manufactured by various methods, can be manufactured by adopting a process of a PCB, can be manufactured by adopting a laser direct writing process on the surface of a magnetic core, can also be directly wound by adopting a copper sheet, and can be manufactured by adopting a mixed process. Optionally, a part of the secondary winding S1 is located on the second metal layer of the bendable substrate, and the other part of the secondary winding S is located on the third metal layer of the bendable substrate. Similarly, the secondary winding S2 has the same distribution characteristics, and will not be described again. Or the secondary winding S1 is located only in the second metal layer and the secondary winding S2 is located only in the third metal layer. Alternatively, the secondary windings S1 and S2 may be formed on a copper sheet to be covered, not limited to the bendable substrate structure. The invention also provides a preparation method of the magnetic element, which comprises the following steps: providing a magnetic core, wherein the magnetic core comprises at least one magnetic column; forming a first metal wiring layer on the surface of the magnetic column to obtain a magnetic core assembly, wherein the first metal wiring layer forms a first winding; providing a bendable substrate, wherein the bendable substrate comprises a second metal wiring layer and a third metal wiring layer, the second metal wiring layer and the third metal wiring layer form a second winding and a third winding, and the number of turns of the second winding and the third winding is smaller than that of the first winding; combining the bendable substrate with the magnetic core assembly so that the second winding at least partially surrounds the outer side of the first winding and the third winding at least partially surrounds the outer side of the second winding, and obtaining the magnetic element.

The implementation of the method for manufacturing the magnetic element is specifically described below in connection with the second embodiment. This production method can be used to produce the magnetic elements shown in fig. 7 to 11 of the first embodiment described above.

A magnetic element structure as shown in fig. 12, the magnetic element comprising:

a magnetic core assembly, the magnetic core comprises a first magnetic column 91, a first metal layer 51 is preset on the surface of the first magnetic column 91, and a first insulation layer 541 is arranged between the first metal layer 51 and the first magnetic column 91;

a bendable substrate, which includes a second metal layer 52 and a third metal layer 53, and a third insulating layer 543 is disposed between the second metal layer 52 and the third metal layer 53;

the magnetic core assembly and the bendable substrate are assembled and a magnetic element is formed through an adhesive layer, and a second insulating layer 542 is arranged between the magnetic core assembly and the bendable substrate.

With respect to the structures shown in fig. 7, 8, 9 (a) and 9 (b), the following first describes the process flow of the first metal layer 51:

step 1: a first insulating layer 541 is formed on the surface of the first magnetic pillar 91 as shown in fig. 14 (a).

In the present embodiment, the magnetic core 93 may be a ring formed by a single magnetic pole, or may be a triangular ring formed by a plurality of magnetic poles, a zigzag shape, a field shape, or other shapes, and the specific structure of the magnetic core is not limited herein. As shown in fig. 13, the magnetic core is a ring-shaped body formed by connecting at least one section of magnetic columns end to end, for example, a zigzag structure formed by connecting the sections of magnetic columns end to end, wherein the magnetic core comprises a square window. The magnetic core 93 may be integrally formed by a plurality of magnetic columns, or may be formed by separately manufacturing and splicing a plurality of magnetic columns. In the process of manufacturing the magnetic core, a window may be first provided on the magnetic core 93, and the window may be formed directly by a mold during the molding of the magnetic core, or may be formed by processing on a magnetic substrate, where the first mode has the characteristic of easy processing, and the second mode has the advantage of high dimensional accuracy, but the invention is not limited thereto.

The process may be defined as the first magnetic pillar 91 by taking a section of the magnetic pillar as an example, and the first insulating layer 541 formed on the surface of the first magnetic pillar 91 may be formed on the surface of the first magnetic pillar 91 by spraying, dipping, electrophoresis, electrostatic spraying, chemical vapor deposition, physical vapor deposition, sputtering, vapor deposition or printing, for example. The first insulating layer 541 generally has the following functions: (1) insulating functions such as: when the magnetic material is a material with lower surface insulation resistance, such as MnZn ferrite, an excessive layer can be added to reduce inter-turn leakage; for a transformer needing to be isolated, the primary side and the secondary side need higher withstand voltage requirements, and a transition layer can be arranged on the surface of the magnetic core to meet the requirements of safety regulations and withstand voltage; further, as a material of a transition layer which is generally used as an insulating layer, there are epoxy resin, silicone, acetal material, polyester imide material, polyimide material, parylene, and the like; (2) a binding force enhancing function such as: when the bonding force between the surface of the magnetic material and the subsequent metal wiring layer is poor, a bonding force reinforcing coating such as epoxy resin and the like can be coated, so that the bonding force between the magnetic material and the subsequent layer is good, or the magnetic material is easy to have good bonding force through surface treatment (such as roughening, surface modification and other processes); (3) stress relief functions, such as: when the selected magnetic material is a stress sensitive material, such as ferrite material, a stress release material, such as organosilicon, may be provided to avoid or reduce the stress generated by the subsequent process on the magnetic material, thereby causing degradation of magnetic properties, such as increased loss or reduced permeability; (4) Core protection (avoiding materials directly adjacent to the core from affecting the properties of the magnetic material); (5) Surface leveling functions, such as improving the surface flatness of the core, facilitating smooth subsequent processing, etc.

Step 2: a first metal layer 51 is formed on the surface of the first insulating layer 541 as shown in fig. 14 (b).

Forming a first metal layer 51 made of copper or copper alloy on the surface of the first insulating layer 541 by a metallization process, wherein the metallization process includes electroplating and electroless plating, and if the thickness of the first metal layer 51 is required to be thinner (for example, 10-20 um), the first metal layer can be realized by an electroless plating method, but the through-flow requirement is smaller; when the through-current requirement is high, the first metal layer 51 may be formed by electroplating, and the seed layer may be disposed by electroless plating, sputtering or vapor deposition to perform the functions of surface conduction and adhesion enhancement. In practical applications, the first metal layer 51 may be formed on the surface of at least one section of the magnetic pillar of the magnetic core by electroplating or electroless plating technology. It should be noted that the first metal layer 51 may be formed only on the surface or a part of the side surface of a section of the magnetic pillar, which is not limited to the present invention.

Step 3: a first metal protective layer 551 is formed on the above-described portion of the first metal layer 51, as shown in fig. 14 (c).

In one possible embodiment, the first metal protective layer 551 composed of tin, tin alloy, gold, or gold alloy may be formed on the first metal layer 51 by electroplating or electroless plating technique. The advantage of using tin as the protective layer is that the cost is low, the reaction rate in a strong oxidizing solvent is extremely slow, and the protective effect is excellent. In addition, in the embodiment, the first metal protection layer 551 may be formed by electroplating or electroless plating, instead of using a conventional non-metal material such as photoresist, and the main reason is that the patterning of the photoresist is realized by exposure and development, and the current exposure machine can only be generally performed on the basis of the same plane, and the structure in the embodiment also needs to perform patterning on the side wall in the window to form the winding around the magnetic pillar, so the exposure and development process is not applicable. Moreover, the first metal protection layer 551 has the following advantages over the general organic material: firstly, the difficulty of uniformly coating photoresist materials such as organic materials is relatively high, particularly, uneven thickness can occur at corners and other positions, so that the consistency of the process is low, and a metal coating is adopted as a metal protection layer, because the surface covering capability of electroplating or electroless plating molding is excellent; next, if an organic material is used as the protective layer, a solution etching process is generally used to etch the metal of the first metal layer 51, after the etching of the wiring metal layer, such as a copper layer, since the solution etching process has a certain isotropy, there is a partial gap under the organic material, and when the organic material is kept for a subsequent process such as spraying an insulating layer, there is a certain shadow and shielding effect at the gap under the organic layer, so that the problem of bad manufacturability, such as bubbles, is generated, and if the entire organic material is removed, there is a certain difficulty, such as organic solvent pollution, long process time, surface cleaning, and the like. In summary, in this embodiment, the first metal protection layer 551 may be formed by electroplating or electroless plating.

In addition, in one possible embodiment, the thickness of the first metal protection layer 551 may be adjusted according to the protection capability of different metals, for example, if the material of the first metal protection layer 551 is tin or tin alloy, the thickness of the first metal protection layer 551 ranges from 1 um to 20um; alternatively, if the material of the first metal protection layer 551 is gold or gold alloy, the thickness of the first metal protection layer 551 is in the range of 0.1-2um.

Step 4: a portion of the first metal protection layer 551 is removed by a direct write technique to expose the first metal layer 51 that needs to be etched away, as shown in fig. 14 (d).

In this embodiment, fig. 14 (d) is a cross-sectional view of a portion of the first metal protection layer 551 removed by the direct-write technique, and one surface of the first metal protection layer 551 is patterned by the direct-write technique, so that a portion of the first metal layer 51 is exposed, i.e., the wiring layer metal to be etched is exposed.

In one possible embodiment, the direct write technique may be, for example, a laser direct write technique. The direct writing technique is characterized in that a focused beam, an electron beam, an ion beam or the like is adopted to directly define a pattern, compared with the traditional photoetching process under the protection of a mask. By adopting the direct writing technology, the production is flexible because no mask is needed, and the serialized products can be produced according to different application requirements, so that the time of the products to the market can be greatly improved. In addition, because the direct writing technology is adopted, the sample and the surface state of the sample can be accurately positioned by the optical identification technology before direct writing, and the direct writing path of each sample can be independently optimized based on the direct writing technology, so that the effect of increasing the yield and reducing the requirement on the previous process is achieved, and the competitiveness of the product is improved. Moreover, since the first metal protection layer 551 is disposed on the first metal layer 51, the first metal layer 51 can perform a good thermal isolation function during laser direct writing to avoid the influence on the magnetic material.

Step 5: the exposed first metal layer 51 is etched to form a desired structure of the first metal layer 51, as shown in fig. 14 (e).

Step 6: the remaining first metal protective layer 551 is removed as shown in fig. 14 (f).

Specifically, whether or not the removal of the first metal protective layer 551 is performed may be selected according to the material of the first metal protective layer 551. For example, when tin is used as the protective layer, after the corresponding pattern is etched on the metal layer, it is possible to select whether the tin protective layer is removed with an etching solution according to the need. Of course, if the protective layer is gold, it may be left, and since the thickness of the gold protective layer is extremely thin, the edge portion may be removed by a water jet, sand blast, or ultrasonic process.

Next, a process for manufacturing the bendable board is described as shown in fig. 15 (a) to (c).

Step 1: the second metal wiring layer 562 and the third metal wiring layer 563 of the preform portion are as shown in fig. 15 (a). A glue substrate 571 is selected, and the substrate 571 is composed of copper foil, glue, and Polyimide (PI). I.e. the double sides of PI are glued and then the copper foil is pressed in to form the double-sided glued substrate 571. The thickness of the pressed copper foil can be freely selected according to the through-flow requirement.

Alternatively, the substrate 571 may be a non-adhesive substrate 571, and compared with a common adhesive substrate 571, the substrate 571 has less intermediate adhesive layers, only comprises two parts of copper foil and PI, and has the advantages of being thinner, better in dimensional stability, higher in heat resistance, higher in bending resistance, better in chemical resistance and the like compared with the adhesive substrate 571.

Step 2: via communication between the second metal wiring layer 562 and the third metal wiring layer 563 is formed as shown in fig. 15 (b).

On the basis of fig. 15 (a), the second metal wiring layer 562 and the third metal wiring layer 563 are connected through the connection hole by a drilling process and a metallization process, and the structure shown in fig. 15 (b) is formed subsequently for the third metal wiring layer 563 by an etching process.

Step 3: the second metal protective layer and the third metal protective layer are formed as shown in fig. 15 (c).

Specifically, the second metal protection layer and the third metal protection layer may be formed by pressing, and the pressing material may be flexible ink or epoxy resin, which is not limited herein.

After the magnetic core assembly and the bendable substrate are manufactured, the bendable substrate and the magnetic core assembly are assembled to form a magnetic element through post assembly, as shown in the schematic cross section of fig. 12, two free ends, namely a first end and a second end, of the bendable substrate are located above the magnetic core assembly, the bendable substrate and the magnetic core assembly are bonded together through a bonding layer 1-5, and the bonding layer 1-5 is marked as 881-885 in the figure to form the magnetic element. The bonding layer material can be a thermosetting material such as silicone resin, epoxy resin, etc. At this time, the second metal wiring layer 562 of the bendable substrate forms the second metal layer 52 of the magnetic element, the third metal wiring layer 563 of the bendable substrate forms the third metal layer 53 of the magnetic element, the second metal protection layer of the bendable substrate forms the second insulating layer 542 of the magnetic element, and the base 571 of the bendable substrate forms the third insulating layer 543 of the magnetic element. A first end of at least one of the second insulating layer 542 and the third insulating layer 543 is below a second end.

Fig. 16 to 18 are schematic views of a magnetic element and a manufacturing method according to a third embodiment of the present invention. In this embodiment, the third insulating layer is partially reinforced 572 based on the second embodiment, and the partially reinforced 572 is located on the upper and lower surfaces of the magnetic element. Pads are formed on the upper and lower surfaces of the core member for connection to external structures, so that it is necessary to secure sufficient flatness. According to the embodiment, on the basis that the bendable substrate can be bent, the third insulating layer is locally toughened, so that the rigidity of the bendable substrate on the upper surface and the lower surface of the magnetic element can be effectively improved, and good flatness is further guaranteed.

The process route of the bendable substrate is as shown in fig. 17 (a) to (c):

specifically, a single-sided copper-clad plate is selected, the substrate 571 of the copper-clad plate is a rigid substrate 573, and a partial area of the rigid substrate 573 is removed by a removing process, and may be removed by a physical manner or a chemical manner, for example, a laser engraving process, which is not limited herein.

Another single-sided copper-clad plate is selected, the substrate 571 of the copper-clad plate is a flexible substrate, and a partial region of the flexible substrate 574 is removed by a removal process.

The two single-sided copper clad laminates are laminated to form a double-sided copper clad laminate comprising a second metal wiring layer 562 and a third metal wiring layer 563, and the substrate between the second metal wiring layer 562 and the third metal wiring layer 563 comprises a rigid substrate 573 and a flexible substrate 574.

The structure of the magnetic element shown in fig. 16 is formed by subsequent post-assembly with the first magnetic pillar 91 through a bendable process. The second metal wiring layer 562 forms the second metal layer 52 of the magnetic element, the third metal wiring layer 563 forms the third metal layer 53 of the magnetic element, and the third insulating layer 543 between the second metal layer 52 and the third metal layer 53 includes a rigid region and a flexible region.

Compared with the first embodiment, in combination with the process of the present embodiment, it is obvious that the thickness of the structure of the present embodiment is the same as that of the first embodiment, and the thickness of the magnetic element is not increased due to the local tempering of the third insulating layer.

Alternatively, based on the first embodiment, a reinforcing layer 575 is provided on the surface of the bendable substrate, as shown in fig. 18. The reinforcing layer 575 layer may be disposed on the surface of the bendable substrate after the bendable substrate is formed, and the material of the reinforcing layer may be completely the same as that of the third insulating layer, except that the reinforcing layer 575 may be thicker than the third insulating layer 543, for example, PI material. The reinforcing layer 575 may also be made of glass fiber reinforced prepreg (PP), or metal material, which is not limited herein.

Fig. 19 (a) and 19 (b) are schematic structural views of another power module according to the fourth embodiment, wherein fig. 19 (a) is a sectional view of the power module along the thickness direction, and fig. 19 (b) is a top view along c-c'. Fig. 20 and 21 are schematic structural diagrams of an interposer included in the power module, wherein fig. 20 is a perspective view including a dielectric insulating layer, and fig. 21 is a perspective view after the dielectric insulating layer is peeled off.

Comparing the first three embodiments, it is apparent that the first end 951 and the second end 952 of the bendable substrate 95 are both located on the upper surface of the magnetic element. From an assembly accuracy standpoint, since the first end 951 and the second end 952 are unconstrained, there must be relative positional tolerances between the pins at the first end 951 and the pins at the second end 952 during assembly, and thus the resulting magnetic element has relatively poor pin dimensional accuracy. Therefore, in order to further optimize the dimensional accuracy of the pins, the first end 951 and the second end 952 are disposed at the sides of the first magnetic pillar 91 (the second magnetic pillar 92), so that all the pins on the upper surface of the magnetic element are located at the same end of the bendable substrate 95, and therefore, the relative positional tolerance between the pins is reduced, and the dimensional accuracy of the pins is improved. The side of the first end 951 and the second end 952 are defined herein as the third side of the magnetic element. Under the same plane size, the size precision of the pins is improved, the size of the bonding pads can be made larger, and meanwhile, the distance between the pins is made smaller, so that the overcurrent area between the magnetic element and the first carrier plate is increased, the power loss is reduced, and the power supply efficiency of the module is improved. In this embodiment, the second winding 46 is connected to a second pin (second power pin 22 and third power pin 23 in fig. 19 b), the third winding 47 is connected to a third pin (first power pin 21 and fourth power pin 24 in fig. 19 b), and the second pin and the third pin are electrically connected to a first transition pin and a second transition pin, respectively, which are located on a third side of the magnetic element. In this embodiment, the second pins include a second power pin 22 and a third power pin 23 shown in fig. 19 (b), and the third pin includes a first power pin 21 and a fourth power pin 24 shown in fig. 19 (b). The first transition pins include a fourteenth power pin 214 and a fifteenth power pin 215 shown in fig. 19 (a), and the second transition pins include a thirteenth power pin 213 and a sixteenth power pin 216 shown in fig. 19 (a).

Referring to the sectional view shown in fig. 19 (a), since the first end 951 and the second end 952 of the bendable substrate 95 are disposed at the sides of the first magnetic pillar 91 or the second magnetic pillar 92, an adapter plate 6 is required to be introduced to connect the first end 951 and the second end 952, and thus the magnetic element of the present embodiment further includes an adapter plate 6 according to the foregoing embodiment. Further, the first end 951 and the second end 952 of the bendable substrate 95 corresponding to the first magnetic pillar 91 and the second magnetic pillar 92 may share the same interposer 6. The pins on the first end 951 and the second end 952 for connecting with the interposer 6 may be set as large as possible even if there is a large relative position tolerance between the pins on the interposer 6 and the pins, so as to envelope the relative position tolerance between the first end 951 and the second end 952. As shown in fig. 20 and 21, the first power pin 66 and the third power pin 68 of the interposer 6 may be connected to the thirteenth power pin 213 and the sixteenth power pin 216 on the first end 951 and the second end 952 of the bendable substrate 95, respectively, and the second power pin 67 of the interposer 6 may be connected to the fourteenth power pin 214 and the fifteenth power pin 215 on the first end 951 and the second end 952 of the bendable substrate 95. Since the first power pin 66 and the second power pin 67 of the interposer 6 are located on the first metal wiring layer 61 of the interposer 6 and are independent of each other, it is necessary to connect together through the second metal wiring layer 62 of the interposer 6. Similarly, the first end 951 and the second end 952 of the bendable substrate 95 corresponding to the second magnetic pillar 92 are connected by the third metal wiring layer 63 and the fourth metal wiring layer 64 of the interposer 6, and other connection methods are also possible, and are not limited to the connection method shown in fig. 20.

Compared with the previous embodiment, the staggered routing of the two layers of secondary windings is realized on the first carrier plate 81, and in this embodiment, the first power pin 21, the second power pin 22, the third power pin 23 and the fourth power pin 24 of the magnetic element are arranged at the same end, so that the windings can be staggered on the bendable substrate 95, and then the windings are directly led out through the wiring of the first carrier plate 81, and the staggered routing is not required to be performed through the first carrier plate 81, so that the resources of the first carrier plate 81 can be effectively saved.

Alternatively, the adapter plate 6 is disposed at a height lower than the upper surface of the magnetic element, so that some passive elements 96, such as resistors, capacitors, etc., may be disposed at the hollowed-out position, as shown in fig. 22 (a) and 22 (b). Fig. 22 (a) is a cross-sectional view of the power module along the thickness direction, and fig. 22 (b) is a top view of the power module along d-d'. Through the power module, voltage conversion is realized, a certain number of input capacitors are needed, the input capacitors are arranged between the adapter plate and the first carrier plate 81, and compared with the case that the input capacitors are arranged on a system board, the input-output loop can be effectively reduced, the impedance is reduced, and the efficiency is improved.

Alternatively, pins may be provided on the upper and lower surfaces of the interposer 6, as shown in fig. 23 (a) and 23 (b). Fig. 23 (a) is a sectional view of the power module along the thickness direction, and fig. 23 (b) is a plan view of the power module along e-e'. Referring to fig. 23 (b), pins 1 to 13 may be used for routing signal lines such as driving and controlling, or routing power, that is, a plurality of signal pins may be provided on the interposer 6, and the plurality of signal pins may be arranged along the first direction. Therefore, only the winding wiring of the secondary side needs to be arranged on the bendable substrate 95, only the power pins of the secondary side are formed on the bendable substrate 95, the pins of the primary side winding are still led out through the conductive piece, and other required pins can be arranged on the adapter plate 6, so that the manufacture of the bendable substrate 95 is simpler and the subsequent assembly is more convenient. Moreover, by making full use of the space of the adapter plate 6, convenience is provided for the extraction electrode.

The magnetic element and the power module provided by the invention can be used for a high-voltage insulation occasion. Next, taking a magnetic element of the fifth embodiment shown in fig. 26 as an example, a first metal layer 51, a second metal layer 52, and a third metal layer 53 are provided in this order from the inside to the outside of the magnetic core. The primary winding is located on the first metal layer, and the two secondary windings are located on the second metal layer 52 and the third metal layer 53, wherein the two secondary windings are formed on a bendable substrate, and the primary winding is directly wound on the magnetic column through copper foil, or is formed on the surface of the magnetic column through metallization. Since the voltage of the primary and secondary sides is relatively high, for example up to 3KV, an effective insulation process between the primary and secondary sides is required. One possible processing method is to press three layers of insulating medium 54 on the surface of the bendable substrate, so that the interlayer insulation between the primary and secondary sides can be fully satisfied. In view of the fact that the area between the two free ends of the bendable substrate is open, the secondary side is directly exposed to air, so that in order to increase the creepage distance L of the primary secondary side, the insulating layer at one end of the bendable substrate can be extended to the position below the other end. The treatment mode of the invention is not limited to the method, and the insulating medium can be coated on the surface of the first metal layer to meet the insulating requirement of the primary side and the secondary side.

Fig. 27 is a schematic structural view of a magnetic element according to a sixth embodiment of the present invention. This embodiment differs from the first embodiment in that: the magnetic element comprises a first winding 45, a second winding 46 and a fourth winding 48, wherein the fourth winding 48 surrounds the outer side of the first magnetic pillar 91 and is at least partially positioned on the inner side of the first winding 45, the fourth winding 48 is a foil winding, the number of turns of the fourth winding 48 is less than or equal to that of the first winding 45, the fourth winding 48 has a fourth winding first projection on the first side surface of the magnetic element, the fourth winding first projection has two boundaries 410 and 420 arranged along the first direction, and the fourth pin first projection extends from one boundary 410 to the other boundary 420 of the fourth winding first projection. The first winding 45 is connected to a first pin 212, 29, the first pin 212, 29 having a first pin first projection on a first side surface of the magnetic element, the first pin first projection being at least partially outside the fourth winding first projection.

The fourth winding 48 is connected to a fourth pin 241, 242, the fourth pin 241, 242 being located on a first side of the magnetic element (e.g. the upper surface of the magnetic element in the view of fig. 27), the fourth pin 241, 242 having a fourth pin first projection on the first side surface of the magnetic element, the fourth winding 48 having a fourth winding first projection on the first side surface of the magnetic element, the fourth pin first projection being located within the fourth winding first projection. In another embodiment, the fourth pin is located on a second side of the magnetic element (e.g., the lower surface of the magnetic element in the perspective of fig. 27), the fourth pin has a fourth pin second projection on the second side surface of the magnetic element, the fourth winding 48 has a fourth winding second projection on the second side surface of the magnetic element, the fourth winding second projection has two boundaries aligned along the first direction, the fourth pin second projection extends from one boundary to the other boundary of the fourth winding second projection, and the fourth pin second projection is located within the fourth winding second projection.

As shown in fig. 27, the second windings 46 are all located outside the fourth windings 48, the second windings 46 are connected to the second pins 22, 23, and the second pins 22, 23 have a second pin first projection on the first side surface of the magnetic element. The fourth pin first projections are located between the two second pin first projections. In yet another embodiment, the fourth pin and the second pin are located on a second side of the magnetic element, respectively, the second pin having a second projection of the second pin on a second side surface of the magnetic element. The fourth pin second projection is located between the second pin second projections of the two second pins on the second side surface of the magnetic element. In another embodiment, a fourth winding first projection of the fourth winding 48 on the first side surface of the magnetic element and a second winding 46 first projection of the second winding 46 on the first side surface of the magnetic element are coincident, and/or a fourth winding second projection of the fourth winding 48 on the second side surface of the magnetic element and a second winding 46 second projection of the second winding 46 on the second side surface of the magnetic element are coincident.

In another embodiment, the fourth winding 48 is located at least partially outside the second winding 46. The two fourth pins and the two second pins are staggered. In yet another embodiment, the second winding 46 is connected to the second pins 22 and 23, two ends of the fourth winding 48 are electrically connected to two ends of the second pins 22 and 23, respectively, and the projection of the connection between the fourth winding 48 and the second pins 22 and 23 on the first side surface of the magnetic element is at least partially outside the first projection of the second winding 46, and the second pins 22 and 23 are used as pins of the fourth winding 48 at the same time.

1. by adopting the magnetic element in the embodiment of the invention, the winding with more turns can be prevented from being penetrated, the loss of the magnetic element is reduced, the reliability of the whole power module is improved, and the possibility of processing safety insulation is provided;

2. the continuous and complete copper sheets are used for replacing the PCB through holes, so that the copper laying efficiency is improved, and the loss is reduced;

The invention has been described with respect to the above-described embodiments, however, the above-described embodiments are merely examples of practicing the invention. It should be noted that the disclosed embodiments do not limit the scope of the invention. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims

1. A magnetic element, comprising:

a first winding surrounding the outside of the magnetic pole;

2. The magnetic component of claim 1, wherein the number of turns of the second winding is greater than or equal to the number of turns of the third winding.

3. The magnetic element of claim 1 wherein the second and third windings are foil windings.

4. A magnetic element according to claim 3, characterized in that the second winding is at least partly surrounding the outside of the third winding.

5. A magnetic element according to claim 3, wherein the first winding is connected to a first pin, the first pin being located on a first side of the magnetic element and having a first pin first projection on a first side surface of the magnetic element, the second winding and the third winding having a second winding first projection and a third winding first projection, respectively, on the first side surface of the magnetic element, the first pin first projection being located at least partially outside the second winding first projection or the third winding first projection.

6. The magnetic component of claim 5, wherein the second winding is connected to a second pin, the third winding is connected to a third pin, the second pin and the third pin are located on a first side of the magnetic component, and the first side surface of the magnetic component has a first projection of the second pin and a first projection of the third pin, respectively.

7. The magnetic element of claim 6 wherein the second pin first projection is located within the second winding first projection, the second winding first projection having two boundaries aligned along the first direction, the second pin first projection extending from one boundary to the other boundary of the second winding first projection.

8. The magnetic element of claim 6 wherein the third pin first projection is located within the third winding first projection, the third winding first projection having two boundaries aligned along the first direction, the third pin first projection extending from one boundary to another boundary of the third winding first projection.

9. A magnetic component as claimed in claim 3, wherein the second winding is connected to a second pin, the third winding is connected to a third pin, the second pin and the third pin are located on a second side of the magnetic component, and have a second pin second projection and a third pin second projection, respectively, on a second side surface of the magnetic component, and the second winding and the third winding have a second winding second projection and a third winding second projection, respectively, on a second side surface of the magnetic component.

10. The magnetic element of claim 9 wherein the second pin second projection is located within the second winding second projection, the second winding second projection having two boundaries aligned along the first direction, the second pin second projection extending from one boundary to the other boundary of the second winding second projection.

11. The magnetic element of claim 9 wherein the third pin second projection is located within the third winding second projection, the third winding second projection having two boundaries aligned along the first direction, the third pin second projection extending from one boundary to the other boundary of the third winding second projection.

12. The magnetic element of claim 5, wherein the first side surface of the magnetic element is provided with a plurality of signal pins, and wherein the projection of the signal pins on the first side surface of the magnetic element does not coincide with any of the first pin first projection, the second winding first projection, and the third winding first projection.

13. The magnetic element of claim 5 wherein the second side surface of the magnetic element is provided with a plurality of signal pins, the second winding and the third winding having a second winding second projection and a third winding second projection, respectively, on the second side surface of the magnetic element, the projections of the signal pins on the second side surface of the magnetic element not coinciding with the second winding second projection and the third winding second projection.

14. The magnetic component of claim 1, wherein the magnetic core comprises two magnetic posts, the first winding, the second winding and the third winding are surrounded on the outer side of each magnetic post, and the outermost windings of the two magnetic posts are electrically connected through adhesive glue.

15. The magnetic component of claim 1, wherein the first winding is a primary winding and the second and third windings are secondary windings.

16. The magnetic component of claim 1, wherein the second winding and the third winding are formed from a flexible substrate.

17. The magnetic component of claim 16, wherein the second winding and the third winding are integrally formed.

18. The magnetic element of claim 6 or 9, wherein the second winding is connected to a second pin, the third winding is connected to a third pin, the second pin and the third pin are located on a second side of the magnetic element, and the magnetic element further comprises a conductive member, the conductive member being surface-mounted on the first winding such that an upper surface of the conductive member, an upper surface of the second pin, and an upper surface of the third pin are coplanar.

19. The magnetic component of claim 1, wherein a second insulating layer is between the first winding and the second winding, and a third insulating layer is between the second winding and the third winding.

20. The magnetic element of claim 19 wherein a first end of at least one of the second insulating layer and the third insulating layer is below a second end.

21. A power module, comprising:

the magnetic element of claim 1;

22. The power module of claim 21, comprising at least two of the first rectifier switching tubes and at least two of the second rectifier switching tubes, the at least two first rectifier switching tubes and the at least two second rectifier switching tubes being staggered along the first direction.

23. The power module of claim 21 wherein the first rectifying switch tubes are distributed along the first direction to form a first rectifying switch tube row and the second rectifying switch tubes are distributed along the first direction to form a second rectifying switch tube row, the first rectifying switch tube row and the second rectifying switch tube row being disposed side-by-side.

24. The power module of claim 21, further comprising an interposer located on a third side of the magnetic element, the pins of the second winding and the third winding being electrically connected to a first transition pin and a second transition pin, respectively, the first transition pin and the second transition pin being located on the third side of the magnetic element, respectively, the pins of the second winding and the third winding being connected to the pins of the first rectifying switch tube and the second rectifying switch tube, respectively, through the interposer and the first carrier.

25. The power module of claim 24, wherein the sides of the interposer are further provided with a plurality of signal pins, the signal pins being aligned along the first direction.

26. The power module of claim 24, wherein the interposer has a height that is lower than a height of the first side surface of the magnetic element, and wherein at least one passive element is disposed between the interposer and the first carrier.

27. A method of manufacturing a magnetic element comprising the steps of:

28. The method of manufacturing a magnetic component of claim 27, wherein forming a first metal wiring layer on the surface of the magnetic pillar comprises the steps of:

Forming a first insulating layer on the surface of the magnetic column;

forming a first metal layer on the surface of the first insulating layer;

forming a first metal protection layer on the surface of the first metal layer;

removing part of the first metal protection layer to expose the first metal layer to be etched;

etching the exposed first metal layer to form a first metal wiring layer;

and removing the remaining first metal protection layer.

29. The method of manufacturing a magnetic component of claim 27, wherein the step of providing a bendable substrate comprises:

providing a substrate, and forming a second metal wiring layer and a third metal wiring layer on two sides of the substrate respectively, wherein the substrate is used as a third insulating layer;

forming via communication between the second metal wiring layer and the third metal wiring layer;

and forming a second metal protection layer and a third metal protection layer on one sides of the second metal wiring layer and the third metal wiring layer, which are away from the base material, respectively.

30. The method of manufacturing a magnetic component of claim 29, wherein providing a substrate, forming a second metal wiring layer and a third metal wiring layer on both sides of the substrate, respectively, comprises the steps of:

Providing a rigid substrate, removing part of the area of the rigid substrate, and forming a second metal wiring layer on one side of the rigid substrate;

selecting a flexible substrate, removing part of the area of the flexible substrate, and forming a third metal wiring layer on one side of the flexible substrate;

and combining the rigid substrate and the flexible substrate to obtain an integral substrate, wherein the second metal wiring layer and the third metal wiring layer are respectively formed on two sides of the integral substrate.

31. The method of claim 30, wherein the rigid substrate is at least partially disposed on the upper and lower surfaces of the magnetic element after the bendable substrate is combined with the magnetic core assembly.

32. The method of claim 27, wherein combining the bendable substrate with the core assembly comprises:

combining the bendable substrate and the magnetic component through an adhesive layer;

a second insulating layer is formed between the first metal wiring layer and the second metal wiring layer.